简单的.NET 8 Web API使用Kafka 发布订阅模式,示例api示例
- kafka
当使用Kafka时,我们需要使用Kafka的客户端库来与Kafka集群进行通信。在.NET Core中,可以使用Confluent.Kafka客户端库来实现与Kafka的集成。首先,我们需要在项目中添加Confluent.Kafka库的引用。
首先,使用NuGet包管理器或者命令行工具添加Confluent.Kafka库的引用:
dotnet add package Confluent.Kafka
接下来,我们可以创建一个名为WeatherUpdatesProducer的类,用于生成天气预报数据并将其发布到Kafka的主题中:
// WeatherUpdatesProducer.csusing Confluent.Kafka; using System; using System.Threading; namespaceWebApiDemo { publicclassWeatherUpdatesProducer { privatereadonly IProducer<Null, string> _producer; privatereadonlystring _topicName; public WeatherUpdatesProducer(string bootstrapServers, string topicName) { _topicName = topicName; var config = new ProducerConfig { BootstrapServers = bootstrapServers }; _producer = new ProducerBuilder<Null, string>(config).Build(); } public void ProduceWeatherUpdates() { var rng = new Random(); for (int i = 0; i < 5; i++) { var forecast = new { Date = DateTime.Now.AddDays(i), TemperatureC = rng.Next(-20, 55), Summary = Summaries[rng.Next(Summaries.Length)] }; var message = $"{forecast.Date}: {forecast.Summary}"; _producer.Produce(_topicName, new Message<Null, string> { Value = message }); Thread.Sleep(1000); // 模拟每秒发布一次消息 } } privatestaticreadonlystring[] Summaries = new[] { "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching" }; } }
在这个示例中,我们创建了一个名为WeatherUpdatesProducer的类,它负责生成天气预报数据并将其发布到Kafka的主题中。我们使用Confluent.Kafka库中的IProducer接口来实现与Kafka的通信。
接下来,我们可以创建一个名为WeatherUpdatesConsumer的类,用于订阅Kafka的主题并处理接收到的天气更新消息:
// WeatherUpdatesConsumer.csusing Confluent.Kafka; using System; namespaceWebApiDemo { publicclassWeatherUpdatesConsumer { privatereadonly IConsumer<Ignore, string> _consumer; public WeatherUpdatesConsumer(string bootstrapServers, string groupId, string topicName) { var config = new ConsumerConfig { BootstrapServers = bootstrapServers, GroupId = groupId, AutoOffsetReset = AutoOffsetReset.Earliest }; _consumer = new ConsumerBuilder<Ignore, string>(config).Build(); _consumer.Subscribe(topicName); } public void ConsumeWeatherUpdates() { try { while (true) { try { var message = _consumer.Consume(); Console.WriteLine($"Received weather update: {message.Value}"); } catch (ConsumeException e) { Console.WriteLine($"Error occurred: {e.Error.Reason}"); } } } catch (OperationCanceledException) { _consumer.Close(); } } } }
在这个示例中,我们创建了一个名为WeatherUpdatesConsumer的类,它负责订阅Kafka的主题并处理接收到的天气更新消息。我们使用Confluent.Kafka库中的IConsumer接口来实现消费者的功能。
接下来,在Startup.cs中注册WeatherUpdatesProducer和WeatherUpdatesConsumer服务,并在应用启动时分别调用ProduceWeatherUpdates和ConsumeWeatherUpdates方法:
// Startup.csusing Microsoft.AspNetCore.Builder; using Microsoft.AspNetCore.Hosting; using Microsoft.Extensions.Configuration; using Microsoft.Extensions.DependencyInjection; using Microsoft.Extensions.Hosting; namespaceWebApiDemo { publicclassStartup { public Startup(IConfiguration configuration) { Configuration = configuration; } public IConfiguration Configuration { get; } public void ConfigureServices(IServiceCollection services) { services.AddControllers(); // 注册WeatherUpdatesProducer服务 services.AddSingleton<WeatherUpdatesProducer>(provider => { var bootstrapServers = Configuration["Kafka:BootstrapServers"]; var topicName = Configuration["Kafka:TopicName"]; returnnew WeatherUpdatesProducer(bootstrapServers, topicName); }); // 注册WeatherUpdatesConsumer服务 services.AddSingleton<WeatherUpdatesConsumer>(provider => { var bootstrapServers = Configuration["Kafka:BootstrapServers"]; var groupId = Configuration["Kafka:GroupId"]; var topicName = Configuration["Kafka:TopicName"]; returnnew WeatherUpdatesConsumer(bootstrapServers, groupId, topicName); }); } public void Configure(IApplicationBuilder app, IWebHostEnvironment env, WeatherUpdatesProducer weatherUpdatesProducer, WeatherUpdatesConsumer weatherUpdatesConsumer) { if (env.IsDevelopment()) { app.UseDeveloperExceptionPage(); } app.UseRouting(); app.UseEndpoints(endpoints => { endpoints.MapControllers(); }); // 在应用启动时生成天气预报数据并发布到Kafka weatherUpdatesProducer.ProduceWeatherUpdates(); // 在应用启动时订阅Kafka主题并处理天气更新消息 weatherUpdatesConsumer.ConsumeWeatherUpdates(); } } }
在这个示例中,我们使用Configuration来获取Kafka的连接配置信息,并在应用启动时分别调用WeatherUpdatesProducer的ProduceWeatherUpdates方法来生成天气预报数据并发布到Kafka,以及调用WeatherUpdatesConsumer的ConsumeWeatherUpdates方法来订阅Kafka的主题并处理接收到的天气更新消息。
这样,我们就实现了基于Kafka的消息发布和订阅功能。当应用启动时,会生成天气预报数据并发布到Kafka的主题中,同时也会订阅Kafka的主题并处理接收到的天气更新消息。
// WeatherUpdatesProducer.csusing Confluent.Kafka; using System; using System.Threading; namespaceWebApiDemo { publicclassWeatherUpdatesProducer { privatereadonly IProducer<Null, string> _producer; privatereadonlystring _topicName; public WeatherUpdatesProducer(string bootstrapServers, string topicName) { _topicName = topicName; var config = new ProducerConfig { BootstrapServers = bootstrapServers }; _producer = new ProducerBuilder<Null, string>(config).Build(); } public void ProduceWeatherUpdates() { var rng = new Random(); for (int i = 0; i < 5; i++) { var forecast = new { Date = DateTime.Now.AddDays(i), TemperatureC = rng.Next(-20, 55), Summary = Summaries[rng.Next(Summaries.Length)] }; var message = $"{forecast.Date}: {forecast.Summary}"; _producer.Produce(_topicName, new Message<Null, string> { Value = message }); Thread.Sleep(1000); // 模拟每秒发布一次消息 } } privatestaticreadonlystring[] Summaries = new[] { "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching" }; } } 标签:Web,示例,Kafka,public,WeatherUpdatesProducer,api,var,new,topicName From: https://www.cnblogs.com/Leo_wl/p/17968690